Variable speed drive apparatus for the scanning system of a copy machine

Abstract

A copy machine for reproducing original size, reduced or magnified copies of an original document is disclosed. The original document is supported on a transparent support surface. An optical scanning system is moved past the original document and an image of the document is transmitted to a photosensitive surface which is moved at constant speed. The speed of the optical scanning system is related to the magnification ratio. The scanning system is driven by a plurality of cams mounted upon a common cam shaft. Scanning speed is selected by coupling the scanning system to one of the plurality of cams.

What is claimed is: 
     
       1. In a copying machine for producing variable magnification copies of an original document, a variable speed drive apparatus for driving an optical scanning system at a selected speed, said copying machine including a transparent document support platen,   a photosensitive receptor surface adapted to move at constant speed,   an optical scanning system for transmitting an image of said original document on said transparent support platen to said photosensitive receptor surface,   said variable speed drive apparatus comprising   a plurality of cams mounted for rotation with a common cam shaft,   a plurality of cam follower arms, one of said arms being associated with each of said cams, and   a plurality of selectively engageable latch means for coupling a selected follower arm to said optical scanning system.   
     
     
       2. In a copying machine for producing variable magnification copies of an original document, a variable speed drive apparatus for driving an optical scanning system at a selected speed, said copying machine including a copying machine frame,   a transparent document support platen,   a photosensitive receptor surface driven at constant speed with respect to said copy machine frame,   an optical scanning system for transmitting an image of said original document on said transparent document support platen to said photosensitive receptor surface,   said variable speed drive apparatus comprising   a cam shaft mounted for constant speed rotation on said copy machine frame and carrying a main cam and at least one auxiliary cam,   a main cam follower arm pivotally mounted to said copy machine frame and associated with said main cam,   at least one auxiliary cam follower arm pivotally mounted to said copy machine frame, each of said auxiliary cam follower arms being positioned to engage with one said auxiliary cam, and   selectively engageable latch means for selectively coupling each of said auxiliary cam follower arms to said main cam follower arm for coupling the motion of a selected auxiliary cam to said main cam follower arm such that said main cam follower arm follows the motion of said selected auxiliary cam.   
     
     
       3. The apparatus of claim 2 wherein said selectively engageable latch means comprises a latch bar mounted on said main cam follower arm,   a latch hook pivotally mounted on each of said auxiliary cam follower arms for engaging said latch bar, and   a solenoid mounted on each of said auxiliary cam follower arms adapted to actuate each of said latch hooks in response to an electrical signal.   
     
     
       4. The apparatus of claim 3 wherein said main cam and said auxiliary cams have substantially identical profiles over a portion of their surfaces. 
     
     
       5. In a copying machine for producing variable magnification copies of an original document, a scanning apparatus for scanning a stationary transparent support platen at a selected speed comprising a copying machine frame,   a pair of guide rails,   a movable lens assembly,   a moving photosensitive surface,   a first carriage supported on said guide rails and adapted to travel along a path parallel to said transparent stationary support platen,   a second carriage supported on said guide rails adapted to travel along a path parallel to said transparent stationary support platen,   said first carriage carrying mirrors to transmit an image of said original document received from said second carriage through said lens assembly to a said photosensitive surface,   said second carriage carrying a mirror to transmit an image of said original document to said first carriage,   linkage means interconnecting said first and second carriage means such that motion imparted to said first carriage means drives said second carriage means in the same direction of said first carriage means at a speed which is twice the speed of the first carriage means,   a main cam follower arm pivotally mounted to said frame,   a drive link for mechanically coupling said main cam follower arm to said first carriage,   at least one of auxiliary cam follower arm pivotally mounted to said frame,   a cam shaft rotatably mounted to said frame carrying a main cam and at least one auxiliary cam associated respectively with said main cam follower and said auxiliary cam follower arm, and   selectively engageable latch means for selectively coupling each of said auxiliary cam follower arms to said main cam follower arm for coupling the motion of a selected auxiliary cam to said main cam follower arm such that the motion of a selected cam is transmitted to said first carriage through said drive link comprising   a latch bar mounted on said main cam follower arm,   a latch hook pivotally mounted on each of said auxiliary cam follower arms for engaging said latch bar, and   a solenoid mounted on each of said auxiliary cam follower arms adapted to actuate each of said latch hooks in response to an electrical signal.